[gnome-panel] build: add AX_IS_RELEASE

[Alberts Muktupāvels <muktupavels src gnome org>]

commit f3295ade20bfe9f2ffe621104f0c508a987485ad
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sat Sep 26 05:20:33 2015 +0300

    build: add AX_IS_RELEASE

 configure.ac |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 7606599..d7b56a6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -24,6 +24,12 @@ AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_AUX_DIR([build-aux])
 
 dnl **************************************************************************
+dnl Set release policy
+dnl **************************************************************************
+
+AX_IS_RELEASE([git-directory])
+
+dnl **************************************************************************
 dnl Initialize automake
 dnl **************************************************************************